In recent years, functions of an image processing apparatus which is one of information processing apparatuses have been diversified, and a user authentication function has been widely used. The user authentication function is a function of identifying a user who uses the image processing apparatus. The user authentication function can request the user who uses the image processing apparatus to input certification information and can permit the user to use the image processing apparatus when authentication has succeeded.
Further, the image processing apparatus can execute a job in cooperation with a network resource (a file server and an electronic mail (e-mail) server). When such a job is executed, user authentication in the image processing apparatus and user authentication for using the network resource are required. In such a case, a technique for enabling the user to complete input of a user identification (ID) and a password at one time by single sign-on has been known.
For example, PTL 1 discusses using information registered once by a user when authentication is required again using log-on data to a local computer and another log-on data being cached to implement the single sign-on. This reduces time and labor for the user to input the same certification information a plurality of times and implements the single sign-on.